This invention relates generally to the field of collapsible type shipping containers used for transporting bulky cargo, and which may be placed in generally planar configuration when emptied to facilitate return shipment for refilling. Devices of this general type are widely used in the shipment of bulk particulate materials such as chemicals, raw and partly prepared materials, and the like.
Such containers are often of substantial dimensions, e.g. four feet square, and are sometimes provided with a door in one side wall to facilitate unloading. Where the particulate material is of small size, the presence of the door is not without accompanying difficulties, such as the problem of readily opening the same against the pressure of the load from within, as well as seepage of the contents of the container. Once opened, it is usually impossible to reclose the door before substantially emptying the contents of the container.
Ideally, such containers would benefit by the presence of a large pour spout localized at or near the bottom of the container in a side wall. Unfortunately, conventional foldable pour spouts of a type used in the packaging of salt or powdered soap for domestic use do not lend themselves to installation in collapsible shipping containers. Such spouts are usually constructed of light weight stamped sheet metal hingedly connected at an inner end to an edge of an opening in a container wall. When closed, the side walls of the spout enter the enclosed volume of the container. Where such a spout is placed at a lower edge of a side wall of a large loaded container, the particulate material, under pressure of its own weight contacts the surfaces of the spout, creating sufficient friction to effectively prevent the withdrawal thereof to opened condition.